Search Engine Optimization (SEO) is the process of improving the volume and quality of traffic to a website from search engines using search results. Usually, the earlier a site is presented in the search results, or the higher it "ranks," the more searchers will visit that site. SEO can also target different kinds of searches including image search, local search, and industry-specific vertical search engines.
As a marketing strategy for increasing a site's relevancy, SEO considers how search algorithms work and what people search for. SEO efforts may involve a site's coding, presentation, and structure, as well as, fixing problems that could prevent search engine indexing programs from fully spidering a site. Other more noticeable efforts may include adding unique content to a site, and making sure that the content is easily indexed by search engines and also appeals to visitors.